Heat exchanger

ABSTRACT

A heat exchanger comprises outer fins; a plurality of tubes arranged alternately with the outer fins; and header tanks receiving open ends of the tubes for communication with the tubes. The header tanks each comprise a first member and a second member which are combined to each other. The first member has tube insertion slots into which the open ends of the tubes are inserted, the second member does not have the tube insertion slots. The first member is either a core material having no brazing material layers on outer and inner peripheral surfaces thereof, or a core material having a brazing material layer on an outer peripheral surface thereof but having no brazing material layer on an inner peripheral surface thereof. The second member is brazed to the outer or inner peripheral surface of the first member having no brazing material layer thereon.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional of U.S. application Ser. No.11/037,467, filed Jan. 19, 2005, which is based upon and claims thebenefit of priority from the prior Japanese Patent Applications Nos.2004-011689, 2004-015959 and 2004-021566 filed on Jan. 20, 2004, Jan.23, 2004 and Jan. 29, 2004, respectively; the entire contents of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat exchanger for use in automotiveair-conditioning systems and the like.

2. Description of the Related Art

A conventional heat exchanger includes flat tubes arranged in multiplestages as heat transfer tubes, corrugated outer fins each arrangedbetween the adjacent multistage flat tubes, and a pair of header tanksconnected to opposite open ends of the flat tubes for communication. Acorrugated inner fin is inserted in each tube.

The header tanks each include a pipe, lids closing opposite open ends ofthe pipe, and a partition plate partitioning a passage extendinglongitudinally through the pipe. The pipe has a plurality of multistagetube insertion slots into which the tubes are inserted.

In this heat exchanger, a refrigerant introduced into one of the headertanks through a refrigerant inlet connector flows through the tubesbetween the header tanks in a zigzag path, and finally is dischargedthrough a refrigerant outlet connector fixed to either of the headertanks. During that time, the refrigerant flowing through the heatexchanger exchanges heat with air passing through spaces in the outerfins between the tubes. For example, when the heat exchanger is used asa radiator or a condenser, the refrigerant is cooled and the air isheated. When the heat exchanger is used as an evaporator, therefrigerant is heated and the air is cooled.

In the manufacturing method of the heat exchanger, with the tubes andthe outer fins arranged alternately, the tubes are inserted into thetube insertion slots in the header tanks to form a temporary assembly.Next, the temporary assembly is heated to a predetermined temperature tomelt brazing material on a surface of each component, and then cooled.As a result, the components are bonded (joined) to each other by thecooled brazing material so as to form the heat exchanger.

In the above-described related art, the components constituting the heatexchanger each have a brazing material layer on a peripheral surfacethereof. Therefore, during brazing, molten brazing material flows allover the heat exchanger. Much of the molten brazing material flows intojoint surfaces by capillarity flow. Generally, a core of the heatexchanger, in which the tubes are joined to the outer fins, has a muchgreater total joint area (total contact area) than the header tanks.Therefore, brazing material of the header tanks flows out to the core ofthe heat exchanger during brazing. As a result, the header tanks areshort of brazing material, so that (i) brazing between membersconstituting the header tanks have reduced stability; (ii) brazingbetween the header tanks and the tubes has reduced stability; and (iii)brazing between the header tanks and piping connectors have reducedstability.

In the above-described art, each tube may be formed by bending a singlemetal plate into a tubular shape, or may be formed by combining twometal plates in a tubular shape. The tube in either form includes ametal plate joint (seam). With this tube structure including a seam,during brazing, a molten brazing material in a brazing material layer onthe inner surface of the tube and a molten brazing material in a brazingmaterial layer on the outer surface of the tube flow into or out of thetube through the seam of the tube. At that time, the brazing material isabsorbed into one of the inner side and the outer side of the tube whichhas a larger total joint area, and the other side of the tube becomesshort of brazing material. Generally, the total area of inner jointsurfaces of the tube (joint surfaces between the inner peripheralsurface of the tube and the inner fin) is larger than the total area ofouter joint surfaces of the tube (joint surfaces between the outerperipheral surface of the tube and the outer fins). Therefore, the outerjoint surfaces of the tube (joint surfaces between the outer peripheralsurface of the tube and the outer fins) tend to be short of brazingmaterial.

SUMMARY OF THE INVENTION

It is an object of the present invention to prevent molten brazingmaterial from flowing between a core of a heat exchanger and headertanks during brazing. It is another object of the present invention toprevent molten brazing material from flowing from the inside of tubes tothe outside of the tubes or from the outside of the tubes to the insideof the tubes during brazing.

The inventors of the present invention have noted that a portion of atube having no brazing material layer thereon can prevent flow ofbrazing material.

A heat exchanger according to one aspect of the present inventioncomprises outer fins; a plurality of tubes arranged alternately with theouter fins; and header tanks receiving open ends of the tubes forcommunication with the tubes. The header tanks each comprise a firstmember and a second member which are combined with each other. The firstmember has tube insertion slots into which the open ends of the tubesare inserted, while the second member does not have tube insertionslots. The first member is either a core material which does not havebrazing material layers on outer and inner peripheral surfaces thereof,or a core material having a brazing material layer on an outerperipheral surface thereof but not having a brazing material layer on aninner peripheral surface thereof. The second member is brazed to theouter or inner peripheral surface of the first member which does nothave brazing material layers thereon.

A heat exchanger according to another aspect of the present inventioncomprises tubes; outer fins brazed to outer surfaces of the tubes; andinner fins brazed inside the tubes. Each of the tubes has a seam anddoes not have a brazing material layer on an inner peripheral surfacethereof but has a brazing material layer on an outer peripheral surfacethereof. Each of the inner fins has brazing material layers on bothsurfaces of a core material, and is brazed to the inner peripheralsurface of the tube, avoiding contact with the seam of the tube.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is an elevation view of an entire configuration of a heatexchanger in a first embodiment of the present invention;

FIG. 2 is an exploded perspective view of a header tank and surroundingparts of the heat exchanger;

FIG. 3 is a cross-sectional view of the exchanger header tank at aportion where a tube insertion slot is located;

FIG. 4A is a cross-sectional view of the header tank at a portion wherea lid (or partition) is located; and FIG. 4B is a cross-sectional viewalong line IVB-IVB in FIG. 4A;

FIG. 5 is a cross-sectional view of a tube in the heat exchanger;

FIGS. 6A to 6C are explanatory diagrams illustrating a part of amanufacturing process of the tube;

FIG. 7 is a cross-sectional view along line VII-VII in FIG. 1;

FIG. 8 is an exploded perspective view of a header tank and surroundingparts of a heat exchanger in a second embodiment of the presentinvention;

FIG. 9 is a cross-sectional view of the header tank in the secondembodiment at a portion where a lid (or partition) is located;

FIG. 10 is a cross-sectional view of a header tank of a heat exchangerin a third embodiment of the present invention;

FIG. 11 is a cross-sectional view of a header tank of a heat exchangerin a fourth embodiment;

FIG. 12 is a cross-sectional view of a header tank of a heat exchangerin a fifth embodiment;

FIG. 13 is a cross-sectional view of a header tank of a heat exchangerin a sixth embodiment;

FIGS. 14A and 14B are perspective views of a header tank in amodification; FIG. 14A illustrates the header tank before combining; andFIG. 14B illustrates the header tank after combining;

FIGS. 15A and 15B are perspective views of a header tank in amodification; FIG. 15A illustrates the header tank before combining; andFIG. 15B illustrates the header tank after combining;

FIG. 16 is a cross-sectional view of a header tank of a heat exchangerin a seventh embodiment at a portion where a tube insertion slot islocated;

FIG. 17A is a cross-sectional view of the header tank at a portion wherea lid (or partition) is located; and FIG. 17B is a cross-sectional viewalong line XVIIB-XVIIB in FIG. 17A;

FIG. 18 is a cross-sectional view of a header tank of a heat exchangerin an eighth embodiment at a portion where a tube insertion slot islocated;

FIG. 19A is a cross-sectional view of the header tank at a portion wherea lid (or partition) is located; and FIG. 19B is a cross-sectional viewalong line XIXB-XIXB in FIG. 19A;

FIG. 20 is a cross-sectional view of a header tank of a heat exchangerin a ninth embodiment at a portion where a tube insertion slot islocated;

FIG. 21 is a cross-sectional view of a header tank of a heat exchangerin a tenth embodiment at a portion where a tube insertion slot islocated;

FIG. 22 is a cross-sectional view of a comparative example 1 to theseventh to tenth embodiments, at a portion of a header tank where a tubeinsertion slot is located;

FIG. 23A is a cross-sectional view of a portion of the header tank inFIG. 22 where a lid (or partition) is located; and FIG. 23B is across-sectional view along line B-B in FIG. 23A;

FIG. 24 is a cross-sectional view of a comparative example 2 to theseventh to tenth embodiments, at a portion of a header tank where a tubeinsertion slot is located;

FIG. 25A is a cross-sectional view of a portion of the header tank inFIG. 24 where a lid (or partition) is located; and FIG. 25B is across-sectional view along line XXVB-XXVB in FIG. 25A;

FIGS. 26A, 26B and 26C are diagrams illustrating modifications of thetube in the first to tenth embodiments;

FIG. 27 is a diagram illustrating a modification of the tube in thefirst to tenth embodiments;

FIG. 28 is a diagram illustrating a modification of the tube in thefirst to tenth embodiments;

FIG. 29 is a diagram illustrating a modification of the tube in thefirst to tenth embodiments;

FIG. 30 is an elevation view of an entire configuration of a heatexchanger in an eleventh embodiment;

FIG. 31 is an exploded perspective view of a header tank and surroundingparts of the heat exchanger;

FIG. 32 is a cross-sectional view of the heat exchanger header tank at aportion where a tube insertion slot is located;

FIG. 33A is a cross-sectional view of the header tank at a portion wherea lid (or partition) is located; and FIG. 33B is a cross-sectional viewalong line XXXIIIB-XXXIIIB in FIG. 33A;

FIG. 34 is a cross-sectional view of a tube of the heat exchanger;

FIGS. 35A, 35B and 35C are explanatory views illustrating a part of amanufacturing process of the tube;

FIG. 36 is a vertical cross-sectional view of the heat exchanger in FIG.1;

FIG. 37 is a diagram illustrating a modification 1 of the tube in theeleventh embodiment;

FIG. 38 is a diagram illustrating a modification 2 of the tube in theeleventh embodiment;

FIG. 39 is a diagram illustrating a modification 3 of the tube in theeleventh embodiment;

FIG. 40 is a diagram illustrating a modification 4 of the tube in theeleventh embodiment;

FIG. 41 is a diagram illustrating a modification 5 of the tube in theeleventh embodiment;

FIG. 42 is a diagram illustrating a modification 6 of the tube in theeleventh embodiment;

FIG. 43 is a diagram illustrating a modification 7 of the tube in theeleventh embodiment; and

FIG. 44 is a diagram illustrating a modification 8 of the tube in theeleventh embodiment.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will be described below withreference to the drawings.

First Embodiment

FIGS. 1 to 7 illustrate a heat exchanger in a first embodiment. The heatexchanger in this embodiment is used as a condenser in which acirculating vapor phase refrigerant is condensed while cooled.

Entire Configuration of the Heat Exchanger

As shown in FIG. 1, a heat exchanger 1 in the first embodiment includesa plurality of outer fins 3, a plurality of flat tubes 5 arrangedalternately with the outer fins 3, reinforcing side plates 11 disposedat the outermost ends in the layering direction of the outer fins 3 andthe tubes 5, and a pair of header tanks 7 receiving opposite open endsof each tube 5 for communication with the tubes 5.

A refrigerant inlet connector 15 is attached to one of the header tanks7 (left one in FIG. 1). A refrigerant outlet connector 17 is attached tothe other header tank 7 (right one in FIG. 1). A partition 27 is fittedin each header tank 7 for partitioning the interior of the header tank 7into a plurality of chambers.

When a refrigerant is introduced into the header tank 7 through therefrigerant inlet connector 15, the refrigerant flows through the tubes5 between the header tanks 7 in a zigzag path, and finally is let outthrough the refrigerant outlet connector 17 of the header tank 7. Duringthat time, the refrigerant flowing through the tubes 5 exchanges heatwith air passing outside the tubes 5.

Header Tank

The configuration of the header tanks 7 will be mainly described withreference to FIGS. 2 to 4.

Each header tank 7 includes a rectangular tube pipe 19, and lids 25closing opposite open ends 19 a, 19 a of the pipe 19. The pipe 19 is acombination of a first member 21 and a second member 23 dividedlongitudinally. The partition 27 for partitioning the interior spaceinto a plurality of chambers is disposed in the header tank 7.

Both of the first member 21 and the second member 23 are formed in a Cshape in a cross section. Specifically, the first member 21 includes aflat base 29 orthogonal to the longitudinal direction of the tube 5, anda pair of straight portions 31 projected from opposite sides of the base29 in a generally orthogonal direction, forming a substantially C-shapecross section. The base 29 of the first member 21 has tube insertionslots 33 into which open ends of the tubes 5 are inserted. Like thefirst member 21, the second member 23 includes a flat base 35 orthogonalto the longitudinal direction of the tube 5, and a pair of straightportions 37 projected from opposite sides of the base 35 in a generallyorthogonal direction, forming a substantially C-shape cross section. Thebase 35 of the second member 23 includes an opening (not shown) intowhich a tubular portion 41 of the refrigerant inlet connector 15 (or therefrigerant outlet connector 17) is inserted and fitted.

In this embodiment, the width dimension of the first member 21 (distancebetween the pair of straight portions 31) is set larger than the widthdimension of the second member 23 (distance between the pair of straightportions 37). The first and second members 21, 23 are brazed to eachother with outer peripheral surfaces of the straight portions 37 of thesecond member 23 fitted to inner peripheral surfaces of the straightportions 31 of the first member 21.

The base 35 of the second member 23 is provided with support holes 43for supporting projections 26 a, 26 a of the lids 25. Also, the straightportions 37 of the second member 23 are provided with support grooves 45for supporting wings 26 b, 26 b of the lids 25. The support holes 43 andthe support grooves 45 in the second member 23 allow the lids 25 to bepositioned in place. In this embodiment, the partition 27 has the sameshape as that of the lids 25. The partition 27 also includes aprojection 28 a and wings 28 b, 28 b, and is positioned in place by asupport hole (43) not shown and support grooves (45) not shown formed inthe second member 23.

The materials of the header tanks 7 will be mainly described.

The material of the first member 21 is a core material 21 a having nobrazing material layers on either surface. The C-shaped first member 21has no brazing material layers on its outer and inner peripheralsurfaces.

The material of the second member 23 is a core material 23 a integrallyformed with a brazing material layer 23 c on an entire surface 23 c oneither side. The brazing material layer 23 c is located on the outerperipheral surface of the C-shaped second member 23.

The material of each lid 25 is a core material 25 a integrally formedwith brazing material layers 25 b, 25 c on both surfaces entirely (FIG.4B).

The material of the partition 27 is a core material 27 a integrallyformed with brazing material layers 27 b, 27 c on both surfaces entirely(FIG. 4B).

When the members of the header tank 7 (the first member 21, the secondmember 23 and the lid 25) are assembled, a brazing material layer islocated between joint surfaces of the members. Thus, brazing of theassembled members causes the members of the header tank 7 to be fixed ina unit.

Although the lid 25 and the partition 27 have no brazing material layerson their peripheries (surfaces to be brought into contact with innerperipheral surfaces of the first and second members 21, 23 constitutinga pipe), the brazing material layers 25 b, 25 c on both surfaces of thelid 25 and the brazing material layers 27 b, 27 c on both surfaces ofthe partition 27 are melted to enter the peripheries by capillarityduring brazing. Consequently, the lid 25 and the partition 27 are brazedto the first and second members 21, 23.

Tube

FIGS. 5 and 6A to 6C illustrate a tube 5. The tube 5 has a tubularshape, and is brazed to the header tanks 7 with its opposite endsinserted into the tube insertion slots 33 in the header tanks 7. Thetube 5 includes a corrugated inner fin 49.

With reference to FIGS. 6A to 6C, the manufacturing process of the tube5 will be described. First, a metal plate 5M of a single elongated platewith a core material 5 a integrally formed with a brazing material layer5 c on either surface entirely is prepared as a material 5M of the tube5.

Then, as shown in FIG. 6A, opposite side portions of the metal plate 5Mof an elongated plate material are rolled inward to form joint portions47.

Then, the material 5M is folded into two along the longitudinal centerline so that the brazing material layer 5 c is located at the outerperipheral side of the tube 5. The joint portions 47 at the edges of thefold are joined together to form a tube. At that time, as shown in FIG.5, the inner fin 49 is inserted in the tube 5. The material of the innerfin 49 is a core material 49 a integrally formed with brazing materiallayers 49 b, 49 c on both surfaces as shown in FIG. 5.

Finally, when the heat exchanger 1 is brazed as a whole, the jointportions 47 of the tube 5 are brazed to each other to be a seam, and theinner surface of the tube 5 is brazed to the inner fin 49. As a result,the tube 5 is completed. At the same time, the outer surface of the tube5 is brazed to the outer fins 3, and outer surfaces at opposite ends ofthe tube 5 are brazed to the inner peripheries of the tube insertionslots 33 in the header tanks 7.

Outer Fin

The material of each outer fin 3 is a core material integrally formedwith brazing material layers on both surfaces.

Manufacturing Process of the Heat Exchanger

The manufacturing process of the heat exchanger 1 in this embodimentwill be briefly described.

First, the outer fins 3, the tubes 5, the inner fins 49, the members ofthe header tanks 7 (the first and second members 21 and 23 and the lids25), the partitions 27, the connectors 15 and 17, and the side plates 11and 11, which are made from predetermined materials, are prepared.

Then, these components are formed into their respective predeterminedshapes.

Then, all of the components are assembled and temporarily fixed by a jigor the like to be a temporary assembly.

Then, the temporary assembly is heated in a furnace at a predeterminedtemperature to braze the components together. That is, brazing materiallayers of the components in the temporary assembly are melted at apredetermined temperature and then cooled, thereby to fix the componentsin a unit.

Functions

During brazing, the first member 21 having no brazing material layers onits outer and inner peripheral surfaces separates the brazing materiallayers 5 c of the tubes 5 joined to the first member 21 from othermembers than the tubes 5 (the second member 23, the lids 25 and thepartition 27) joined to the first member 21. In other words, the firstmember 21 having no brazing material layer separates the brazingmaterial layers 5 c of the tubes 5 from brazing material layers of theheader tank 7 (the brazing material layer 23 c of the second member 23,the brazing material layers 25 b, 25 c of the lids 25 and the brazingmaterial layers 27 b, 27 c of the partition 27). Accordingly, duringbrazing, no brazing material is exchanged between the heat exchangercore 1A and the header tanks 7. As a result, the header tanks 7 areprevented from being deprived of brazing material by the heat exchangercore 1A having a large number of capillaries, and being short of brazingmaterial.

Effects

The effects of the first embodiment will be explained below.

First, according to the first embodiment, the first member 21 having nobrazing material layer separates the brazing material layers 5 c of thetubes 5 from brazing material layers of the header tank 7 (the brazingmaterial layer 23 c of the second member 23, the brazing material layers25 b, 25 c of the lids 25 and the brazing material layers 27 b, 27 c ofthe partition 27). Accordingly, the header tank 7 is prevented frombeing deprived of brazing material by the heat exchanger core 1A havinga large number of capillaries, and being short of brazing material. Thisresults in good stability in connection between a part (such as theconnector 15, 17) joined to the header tank 7 and the members (the firstand second members 21, 23 and the lids 25) constituting the header tank7. Also, since brazing material of the header tank 7 does not flow tothe heat exchanger core 1A, unnecessary brazing material does notaccumulate on the tubes 5 and the outer fins 3 in the heat exchangercore 1A. As a result, it never happens that accumulation of brazingmaterial reduces an airflow area between the tubes 5.

Second, according to the first embodiment, the material of the secondmember 23 is the core material 23 a integrally formed with the brazingmaterial layer 23 c entirely on either of the inner peripheral surfaceor the outer peripheral surface (the outer peripheral surface in thisembodiment) which includes a portion joined to the first member 21.Thus, there is no need to previously apply brazing materials X to jointportions of the first member 21 and the second member 23 as shown inFIG. 10 described below. Consequently, the manufacturing process of theheat exchanger 1 is simplified.

Third, according to the first embodiment, in the header tank 7 of a typeincluding the pipe 19 and the lids 25 closing the opposite open ends 19a, 19 a of the pipe 19, the materials of the lids 25 are the corematerials 25 a each integrally formed with the brazing material layers25 b, 25 c on both surfaces entirely. Thus, there is no need topreviously apply brazing material layers to joint portions of the lids25 and the first and second members 21, 23. Consequently, themanufacturing process of the heat exchanger 1 is simplified.

Fourth, according to the first embodiment, in the header tank 7 of atype including the partition 27, the material of the partition 27 is thecore material 27 a integrally formed with the brazing material layers 27b, 27 c on both surfaces entirely. Thus, there is no need to previouslyapply brazing material layers to joint portions of the partition 27 andthe first and second members 21, 23. Consequently, the manufacturingprocess of the heat exchanger 1 is simplified.

Fifth, according to the first embodiment, in the presented type, thefirst member 21 is formed wider than the second member 23, and outerperipheral surfaces of the second member 23 are fitted and brazed toinner peripheral surfaces of the first member 21. Since the material ofthe second member 23 is the core material 23 a integrally formed withthe brazing material layer 23 c on its entire outer surface, the firstand second members 21 and 23 can be joined without applying brazingmaterials X to joint surfaces of the first and second members 21, 23before brazing, unlike a third embodiment in FIG. 10 to be describedbelow. Consequently, the manufacturing process of the heat exchanger 1is simplified (similar to the first effect). Further, since there is noneed to provide brazing material layers to the connector 15 (17), aliquid tank and the like to be connected to the outer peripheral surfaceof the second member 23, the manufacturing process of the heat exchanger1 is further simplified.

Sixth, according to the first embodiment, the material of the tube 5includes the brazing material layer 5 c integrally formed on the entireouter peripheral surface of the tube 5. Thus, there is no need to applybrazing material to a joint region between the tube 5 and the tubeinsertion slot 33. Also, there is no need to apply brazing material tojoint regions between the tube 5 and the outer fins 3. Consequently, themanufacturing process of the heat exchanger 1 is further simplified.

Also, in the structure presented in the first embodiment, the tube 5 hasno brazing material layer on its inner surface, and the inner fin 49 hasbrazing material layers on both sides. Therefore, there is no need toapply brazing material to joint regions between the tube 5 and the innerfin 49 before brazing, and the manufacturing process of the heatexchanger 1 is further simplified.

Seventh, according to the heat exchanger 1 of this first embodiment, thetube 5 is configured to have the joint portions 47. In particular, thejoint portions 47 are provided along the entire length of the tube 5.This configuration causes brazing material of the header tank 7 to belikely to be absorbed into the joint portions 47 of the tube 5 duringbrazing. Thus, the brazing material flow cutoff function of the firstmember 21 (a brazing material flow cutoff portion S2) is more effective.

Eighth, in this first embodiment, in the tube 5 with the joint portions47, the inner fin 49 having the brazing material layers 49 b, 49 c onboth surfaces of the core material 49 a is brazed to the innerperipheral surface of the tube 5, avoiding contact with the jointportions 47 of the tube 5. Therefore, brazing material inside the tube 5(the brazing material layers 49 b, 49 c on both surfaces of the innerfin (49) is separated from brazing material outside the tube 5 (thebrazing material layer 5 c on the outer surface of the tube 5) by thetube inner peripheral surface having no brazing material layer. That is,the inner peripheral surface of the tube 5 has a brazing material flowcutoff portion S3 for preventing the flow of brazing material betweenthe inside of the tube 5 and the outside of the tube 5. Thus, duringbrazing, brazing material inside the tube 5 is prevented from flowingout of the tube 5 through a joint surface between the joint portions 47,and brazing material outside the tube 5 is prevented from flowing intothe tube 5 through a joint surface between the joint portions 47. Thus,either the inside or the outside of the tube 5 never becomes short ofbrazing material. In the first embodiment, the total joint area insidethe tube 5 (the total area of the joint surfaces between the innerperipheral surface of the tube 5 and the inner fin 49) is greater thanthe total joint area outside the tube 5 (the total area of the jointsurfaces between the outer peripheral surface of the tube 5 and theouter fins 3). Thus, during brazing, the brazing material flow cutoffportion S3 prevents brazing material outside the tube 5 from flowingaway into the tube 5 to cause a shortage of brazing material at theoutside of the tube 5.

Other embodiments will be described below.

Second Embodiment

FIGS. 8 and 9 show a heat exchanger 1 in a second embodiment. The heatexchanger 1 in the second embodiment is different from the firstembodiment in the structure of supporting a lid 25 and a partition 27 ina header tank 7. In the second embodiment, support holes 44 areadditionally formed in a first member 21 in the structure of the firstembodiment. Projections 26 c and 28 c to be supported by the supportholes 44 are added to the lid 25 and the partition 27, which isdifferent from the first embodiment.

According to the second embodiment, even with the structure having theholes 44 formed in the first member 21, since a core material 21 a ofthe first member 21 has no brazing material layers on its inner andouter peripheral surfaces, the first member 21 having no brazingmaterial layers on the inner and outer peripheral surfaces can have abrazing material flow cutoff function, as in the first embodiment.

Third Embodiment

FIG. 10 shows a third embodiment. A header tank 100 in the thirdembodiment in FIG. 10 is different from that in the first embodiment inthat a brazing material layer is not integrally formed on the entireouter surface of a second member 102, and a core material 102 a isexposed to the entire second member 102. To ensure a brazed jointbetween a first member 21 and the second member 102, brazing materials Xare applied to joint surfaces between the first member 21 and the secondmember 102 before brazing. At that time, the brazing materials X may beapplied either to the first member 21 or to the second member 102 beforebrazing.

According to the third embodiment, as in the first embodiment, the firstmember 21 having no brazing material layers on its inner and outerperipheral surfaces can provide a brazing material flow cutoff function.

Fourth Embodiment

FIG. 11 shows a fourth embodiment.

The fourth embodiment in FIG. 11 is different from the third embodimentin that a header tank 110 has a second member 112 formed wider than afirst member 21, and outer peripheral surfaces of the first member 21 isfitted and brazed to inner peripheral surfaces of the second member 112.The second member 112 is constituted by a core material, and brazingmaterials X are applied to joint surfaces between the first member 21and the second member 112 before brazing, as in the third embodiment. Atthat time, the brazing materials X may be applied either to the firstmember 21 or to the second member 112 before brazing.

According to the fourth embodiment, as in the first to thirdembodiments, the first member 21 having no brazing material layers onits inner and outer peripheral surfaces can provide a brazing materialflow cutoff function.

Fifth Embodiment

FIG. 12 shows a fifth embodiment. A header tank 120 in the fifthembodiment is different from that in the fourth embodiment in that abrazing material layer 121 b is integrally formed on an entire innerperipheral surface of a core material 120 a of a second member 121.

According to the fifth embodiment, unlike the fourth embodiment, thefirst member 21 can be joined to the second member 121 withoutapplication of brazing materials X to joint surfaces between the firstmember 21 and the second member 112 before brazing. Thus, themanufacturing process of a heat exchanger 1 is more simplified than inthe fourth embodiment.

Sixth Embodiment

FIG. 13 shows a sixth embodiment. A header tank 130 in the sixthembodiment is different from that in the fifth embodiment in that thematerial of a second member 131 is a core material 131 a integrallyformed with brazing material layers 131 b, 131 c on its entire inner andouter peripheral surfaces.

The sixth embodiment eliminates the need for applying or thermalspraying a brazing material to a connector 15 (17) to be connected tothe outer peripheral surface of the second member 131, and thus themanufacturing process of a heat exchanger 1 is more simplified, inaddition to the effect in the fifth embodiment.

In the first to sixth embodiments, a first member 141 and a secondmember 142 of a header tank 140 may be integrally formed with a lid asshown in FIGS. 14A and 14B, for example, if a material of the firstmember 141 is a core material with no brazing material layers integrallyformed on its inner and outer peripheral surfaces. Alternatively, afirst member 141 and a second member 152 of a header tank 150 may beintegrally formed with a lid as shown in FIGS. 15A and 15B, for example.That is, in the first to sixth embodiments, the header tank 140 (headertank 150) may be of a type in which it is longitudinally divided intothe box-shaped first member 141 (first member 151) and second member 142(second member 152) which are combined in the longitudinal direction ofthe tubes, each member having an opening formed in the combiningdirection.

In short, according to the first to sixth embodiments, a first memberconstituted by a core material having no brazing materials on bothsurfaces separates a brazing material layer of a tube from a brazingmaterial layer of a header tank. That is, a first member with no brazingmaterial layer serves as a brazing material flow cutoff portion.Consequently, the header tank is prevented from being deprived ofbrazing material by a heat exchanger core having a large number ofcapillaries, and being short of brazing material. This results in a goodstability in connection between the header tank and a part (such as aconnector) joined to the header tank. Also, tubes and outer fins in theheat exchanger core are prevented from having an accumulation ofunnecessary brazing material.

Seventh to tenth embodiments will be described. The seventh to tenthembodiments are different from the first to sixth embodiments in that afirst member 161 is of a type having a brazing material layer 161 c onits outer surface.

Seventh Embodiment

A header tank 160 in the seventh embodiment is different from that inthe first embodiment in which the first member 21 has no brazingmaterial layers on its inner and outer peripheral surfaces, in that, asshown in FIGS. 16 to 18, a first member 161 has a brazing material layer161 c on its outer surface, and in other respects, is completelyidentical to that in the first embodiment.

When members of the header tank 160 (the first member 161, a secondmember 23, a lid 25) are assembled, a brazing material layer is locatedbetween joint surfaces of the members. The assembled members are brazedat a predetermined temperature, thereby to fix the members of the headertank 160 in a unit.

In a heat exchanger in the seventh embodiment, the first and secondmembers 161 and 23 of the header tank 160 are brazed together with thesecond member 23 fitted to the inner peripheral surface of the firstmember 161. Thus, the inner peripheral surface and edges of the firstmember 161 with no brazing material layers (brazing material flow cutoffportions S2) separate a brazing material layer 23 c for joining thefirst and second members 161 and 23 from a brazing material layer of atube 5. Therefore, during brazing, the brazing material layer 23 c forjoining the first and second members 161 and 23 is prevented fromflowing away to the tube 5 through the inner and outer peripheralsurfaces of the first member 161.

In the heat exchanger in the seventh embodiment, a lid 25 is provided,and the lid 25 is fitted to the inner peripheral surface of a pipe 19consisting of the first member 161 and the second member 23, withbrazing material layers 25 b, 25 c of the lid 25 out of contact with thebrazing material layer 161 c on the outer peripheral surface of thefirst member 161. Thus, the brazing material layers 25 b, 25 c of thelid 25 (brazing material layers 25 b, 25 c for joining the lid 25 to thefirst and second members 161 and 23) are separated from a brazingmaterial layer 5 c of a tube 5 by the inner peripheral surface with nobrazing material layer and edges S2 of the first member 161. Thus, thebrazing material is prevented from flowing away to the tube 5 duringbrazing. Consequently, during brazing, brazing material in the brazingmaterial layers 23 c, 25 b and 25 c for joining the lid 25 to the innerperipheral surfaces of the first and second members 161 and 23 isprevented from flowing away from the inner and outer peripheral surfacesof the first member 161 to the tube 5.

Thus, according to the seventh embodiment, during brazing, the brazingmaterial layer 23 c for joining the first member 161 and the secondmember 23 and the brazing material layers 25 b, 25 c and 23 c forjoining the lid 25 to the first and second members 161 and 23 areprevented from flowing away to the tubes 5.

Effects

The effects of the seventh embodiment will be summarized below.

First, according to the seventh embodiment, the inner peripheral surfaceand the edges S2 with no brazing material layers of the first member 161separates the brazing material layer 5 c of the tube 5 from brazingmaterial layers of the header tank 160 (the brazing material layer 23 cof the second member 23 and the brazing material layers 25 b, 25 c ofthe lid 25). Consequently, the header tank 160 is prevented from beingdeprived of brazing material by a heat exchanger core 1A having a largenumber of capillaries, and being short of brazing material. This resultsin good stability in connection between a part (such as a connector 15or 17) joined to the header tank 160 and members constituting the headertank 160 (the first and second members 161, 23 and the lid 25). Also,since brazing material of the header tank 160 does not flow to the heatexchanger core 1A, unnecessary brazing material does not accumulate ontubes 5 and outer fins 3 in the heat exchanger core 1A. As a result,accumulation of brazing material reducing an airflow area between thetubes 5 never happens.

Second, like the lid 25, a partition 27 is fitted in the pipe 19comprised of the first and second members 161, 23, with its brazingmaterial layers 27 b, 27 c out of contact with the outer peripheralsurface of the first member 161 and tubes 5. Thus, brazing material ofthe header tank 160 does not flow away to the tubes 5 (heat exchangercore 1A) through the brazing material layers 27 b, 27 c of the partition27.

Third, in the heat exchanger 1 in the seventh embodiment, each tube 5 islongitudinally provided with joint portions 47. With this, a brazingmaterial flow cutoff function of the first member 161 is more effective.If the first member 161 did not have the brazing material flow cutofffunction in the seventh embodiment, brazing material of the header tank160 would be further absorbed into the joint portions 47 of the tube 5.

Fourth, according to the seventh embodiment, the second member 23 hasthe brazing material layer 23 c on its outer peripheral surface. Thus,brazing material for joining the second member 23 to the innerperipheral surface of the first member 161 is provided by the brazingmaterial layer 23 c on the outer peripheral surface of the second member23. This eliminates the need for applying brazing materials (X) forjoining a second member (192) to the inner peripheral surface of a firstmember (161) before brazing as in the tenth embodiment described below.

Fifth, according to the seventh embodiment, the lid 25 is in a plateshape, and has the brazing material layer 25 b, 25 c on at least onesurface. Thus, brazing material for joining the lid 25 to the innerperipheral surfaces of the first and second members 161 and 23 isprovided by the brazing material layer 25 b, 25 c of the lid 25. Thiseliminates the need for applying brazing material for joining the lid 25to the inner peripheral surfaces of the first and second members 161 and23 before brazing. In this embodiment, the brazing material layer 23 con the outer peripheral surface of the second member 23 flows over thebrazing material layers 25 b, 25 c of the lid 25, thereby also acting asbrazing material for joining the inner peripheral surfaces of the firstand second members 161 and 23 and the lid 25.

Sixth, according to the seventh embodiment, the partition 27 is in aplate shape, and has the brazing material layer 27 b, 27 c on at leastone surface. This eliminates the need for applying brazing material forjoining the partition 27 to the inner peripheral surfaces of the firstand second members 161 and 23 before brazing. In this embodiment, thebrazing material layer 23 c on the outer peripheral surface of thesecond member 23 flows over the brazing material layer 27 b, 27 c of thepartition 27, thereby also acting as brazing material for joining thepartition 27 to the inner peripheral surfaces of the first and secondmembers 161 and 23.

Eighth Embodiment

FIGS. 18 and 19 show a header tank 170 of a heat exchanger in an eighthembodiment. The header tank 170 in the eighth embodiment has the samestructure as that in the seventh embodiment except that a second member172 has brazing material layers 172 c and 172 b on both inner and outerperipheral surfaces of a core material 172 a, respectively. Even withthis structure in which the second member 172 has the brazing materiallayer 172 b on its inner peripheral surface, the same effects as in theseventh embodiment can be provided.

Ninth Embodiment

FIG. 20 shows a header tank 180 of a heat exchanger in a ninthembodiment. The header tank 180 in the ninth embodiment is differentfrom that in the seventh embodiment in that a first member 161 isprovided with expanding portions 181 expanding in a taperedcross-section shape at edges of a pair of straight portions 31, and edgeportions S2 of the first member 161 are spaced from a brazing materiallayer 23 c on the outer peripheral surface of a second member 23.

According to the ninth embodiment, in addition to the effects in theseventh embodiment, even when the first member 161 is formed thinner,the edge portions S2 of the first member 161 can reliably prevent abrazing material layer 161 c on the outer peripheral surface of thefirst member 161 from connecting to the brazing material layer 23 c onthe outer peripheral surface of the second member 23. This is alsoeffective even if the first member 161 is not thin.

Tenth Embodiment

FIG. 21 shows a header tank 190 of a heat exchanger in a tenthembodiment. The header tank 190 in the tenth embodiment is differentfrom those in the seventh to ninth embodiments in which the secondmembers 23, 172 have the brazing material layers 23 c, 17 c on the outersurfaces, in that a second member 192 is only comprised of a corematerial 192 with no brazing material layer thereon. Thus, beforebrazing of the header tank 190 in the tenth embodiment, brazingmaterials X for joining a first member 161 and the second member 192 areapplied to the first member 161 or the second member 192.

According to the tenth embodiment, similar functions and effects tothose in the seventh to ninth embodiments can be provided. Themanufacturing process of the heat exchanger 1 in the seventh to ninthembodiments is simpler than in that in the tenth embodiment because thebrazing material layer 23 c of the second member 23 joins the firstmember 161 and the second member 23, thus eliminating the need forseparately applying brazing materials X for joining the first member 161and the second member 192 as in the tenth embodiment.

Comparative examples to the seventh to tenth embodiments will bedescribed below. The comparative examples are intended to clarify thestructures and the functions/effects of the seventh to tenthembodiments. Comparative examples 1 and 2 are not conventional examples.

Comparative Example 1

FIGS. 22, 23A and 23B show a comparative example 1. This comparativeexample 1 is out of the scope of the present invention. A header tank200 of a heat exchanger in the comparative example 1 is different fromthose in the seventh to tenth embodiments in which the first member 161has the brazing material layer 161 c only on its outer peripheralsurface, in that a first member 201 has a brazing material layer 201 bon its inner peripheral surface as well as a brazing material layer 201c on its outer peripheral surface.

In this comparative example 1, since the first member 201 has thebrazing material layer 201 b on its inner peripheral surface, a brazingmaterial layer 23 c on the outer peripheral surface of a second member23 (brazing material for joining the first member 201 and the secondmember 23) is in contact with the brazing material layer 21 b on theinner peripheral surface of the first member 201 as shown in FIGS. 22and 23A. The brazing material layer 201 b on the inner peripheralsurface of the first member 21 is in contact with a brazing materiallayer on the outer peripheral surface of a tube 5 projected into thepipe inner peripheral side through a tube insertion slot 33 in the firstmember 21. Therefore, during brazing, the brazing material layer 23 c onthe outer peripheral surface of the second member 23 flows out to thebrazing material layer 5 c on the outer peripheral surface of the tube 5through the brazing material layer 201 b on the inner peripheral surfaceof the first member 21.

In the seventh to tenth embodiments, no brazing material layer isprovided to the inner peripheral surface of the first member 161 whichcan be in contact with the brazing material layers 5 c on the outerperipheral surfaces of the tubes 5. Thus, brazing material of the headertanks 160, 170, 180 and 190 is prevented from flowing out to the tubes5.

Comparative Example 2

FIGS. 24, 25A and 25B show a comparative example 2. This comparativeexample 2 is also out of the scope of the present invention. A headertank 300 of a heat exchanger in the comparative example 2 includes afirst member 21 provided with support holes 44, and a lid 25 and apartition 27 provided with projections 26 c and 28 c supported by thesupport holes 44, in addition to the components in the seventh to tenthembodiments.

In the comparative example 2, the projections 26 c and 28 c of the lid25 and the partition 27 are in contact with a brazing material layer 301c on the outer peripheral surface of the first member 21. Therefore, asshown in FIGS. 24, 25A and 25B, a brazing material layer 23 c on theouter peripheral surface of a second member 23 (brazing material forjoining the first member 21 and the second member 23) flows out to tubes5 through brazing material layers 25 b, 25 c, 27 b and 27 c of the lid25 and the partition 27, through the projections 26 c, 28 c, through thebrazing material layer 301 c on the outer peripheral surface of thefirst member 21, and through brazing material layers on the outerperipheral surfaces of the tubes 5. At the same time, brazing materialin the brazing material layers 25 b, 25 c, 27 b and 27 c of the lid 25and the partition 27 flows out to the tubes 5 in the same route.

In the seventh to tenth embodiments, when the lid 25 and/or thepartition 27 are provided, the lid 25 and/or the partition 27 are fittedin the header tank 160, 170, 180 or 190, with the brazing materiallayers 25 b, 25 c, 27 b and 27 c of the lid 25 and/or the partition 27out of contact with the brazing material layer 161 c on the outerperipheral surface of the first member 161. Thus, brazing material ofthe header tank is prevented from flowing out to the tubes 5. In theseventh to tenth embodiments, to support the lid 25 and/or the partition27 on the first member 161, support portions can be in any shape such asa hole with a bottom or a groove formed in the inner peripheral surfaceof the first member, except for a hole extending from the innerperipheral surface to the outer peripheral surface of the first member.

As described above, according to the seventh to tenth embodiments, aheader tank includes a first member and a second member combined to eachother; the first member includes tube insertion slots, while the secondmember includes no tube insertion slots; the first member has no brazingmaterial layer on its inner surface, while having a brazing materiallayer on its outer surface; and the second member is fitted to the innerperipheral surface of the first member. Therefore, brazing material ofthe header tank (especially brazing material for joining the secondmember to the first member) is prevented from flowing out to tubesthrough the first member.

In any of the seventh to tenth embodiments, a joint surface of a secondmember to a first member is an outer peripheral surface of the secondmember. A joint surface of a second member to a first member may be aninner peripheral surface of the second member, an outer peripheralsurface of the second member, or an edge surface of the second member.

Also, in any of the seventh to tenth embodiments, a header tank isconfigured to include a pipe 19 comprised of a first member and a secondmember, and lids 25 at opposite ends of the pipe 19. However, if a firstmember 141 and a second member 142 are integrally formed with a lid asshown in FIG. 14, for example, the same effects as in the seventh totenth embodiments can be obtained. That is, the header tank 140 may beof a type longitudinally divided into the box-shaped first member 141and second member 142 which are combined in the longitudinal directionof tubes 5, each member having an opening formed in the combiningdirection.

In the structure in any of the first to tenth embodiments, a partitionis provided, but it is possible not to provide a partition.

In the first to tenth embodiments, outer fins and side plates may beconfigured to be in contact with a first member. When outer fins, sideplates and the like are in contact with a first member, and the outerfins and the side plates are provided with brazing material layers,brazing material of a header tank is out of contact with the brazingmaterial layers.

In the first to tenth embodiments, a tube with joint portions is used.Alternatively, a tube with joint portions as in “tube modification 1” or“tube modification 2” described below may be used, or a tube with nojoint portions as in “tube modification 3” described below may be used.

[Tube Modification 1]

Tubes in FIGS. 26A, 26B and 26C are different from the tube in FIG. 5 inthe shape of a joint. The tubes in FIGS. 26A, 26B and 26C are each of atype in which a single metal plate is folded in a tubular shape, likethe tube in FIG. 5.

A tube 50 in FIG. 26A is identical to the tube 5 in the first embodimentin that an elongated plate-like material having a brazing material layer50 on an entire surface to constitute the outer surface of a corematerial 50 a is folded in a tubular shape, and joint portions 51, 52 atopposite sides are brazed to each other, but is different from the tube5 in the first embodiment in that one of the joint portions 51, 52 atthe opposite sides of the material (the upper one 51 in this embodiment)is formed longer than the other one (the lower one 52 in thisembodiment), and is formed in a substantially C shape to enclose theother one. In brazing, an inner surface of the joint portion 51 is incontact with an outer surface of the joint portion 52 having a brazingmaterial layer, whereby the joint portions 51, 52 are brazed to eachother.

A tube 60 in FIG. 26B is identical to the tube 5 in FIG. 5 in that anelongated plate-like material having a brazing material layer 60 c on anentire surface to constitute the outer surface of a core material 60 ais folded in a tubular shape, and joint portions 61 at opposite sidesare brazed to each other, but is different in the shape of the jointportions 61.

A tube 70 in FIG. 26C is identical to the tube 5 in FIG. 5 in that anelongated plate-like material having a brazing material layer 70 c on anentire surface to constitute the outer surface of a core material 70 ais folded in a tubular shape, and joint portions 71 at opposite sidesare brazed to each other, but is different from the tube 5 in FIG. 5 inthat the joint portions 71 are brazed to each other at their innersurfaces with no brazing material layers.

[Tube Modification 2]

FIG. 27 shows another modified tube. A tube 80 in FIG. 27 is differentfrom the tube 5 in FIG. 5 in that two metal plates 80A, 80B are used.The tube 80 is configured such that the two metal plates 80A, 80B arejoined in a tubular shape, and joint portions 81, 82 at opposite sidesare brazed to each other. The tube 80 is similar to the tube 5 in FIG. 5in that it has the joint portions 81, 82 along its entire length.

[Tube Modification 3]

Tubes in the first to tenth embodiments include a seam, but tubes may beformed seamlessly. A tube 90A in FIG. 28 and a tube 90B in FIG. 29 arelongitudinally extruded tubes, and have no seams. The tube 90A in FIG.28 includes a separate inner fin 49; and the tube 90B in FIG. 29 isintegrated with an inner fin.

In the first to tenth embodiments, each outer fin 3 is integrally formedwith brazing material layers on both surfaces, but may alternatively beformed integrally with a brazing material layer only on one surface, ormay have no brazing material layers on both surfaces.

In the first to tenth embodiments, each tube 5 has the brazing materiallayer 5 c not on its inner surface but on its outer surface, butalternatively, a brazing material layer may be provided on the innersurface of the tube 5. If a brazing material layer is provided on theinner surface of the tube 5, an inner fin 49 with no brazing materiallayers on either surface can be used.

Eleventh Embodiment

An embodiment will be described which can prevent brazing material fromflowing from inner surfaces of tubes to outer surfaces of the tubes orfrom outer surfaces of tubes to inner surfaces of the tubes throughseams of the tubes during brazing.

FIGS. 30 to 36 illustrate a heat exchanger in an eleventh embodiment.The heat exchanger in this embodiment is used as a condenser in which acirculating vapor phase refrigerant is condensed while cooled.

Entire Configuration of the Heat Exchanger

As shown in FIG. 30, a heat exchanger 501 in the eleventh embodimentincludes a plurality of outer fins 503, a plurality of flat tubes 505arranged alternately with the outer fins 503, reinforcing side plates511 disposed at the outermost ends in the layering direction of theouter fins 503 and the tubes 505, and a pair of header tanks 507receiving opposite open ends of each tube 505 for communication with thetubes 505.

A refrigerant inlet connector 515 is attached to one of the header tanks507 (left one in FIG. 30). A refrigerant outlet connector 517 isattached to the other header tank 507 (right one in FIG. 30). Apartition 527 is fitted in each header tank 507 for partitioning theinterior of the header tank 507 into a plurality of chambers.

When a refrigerant is introduced into the header tank 507 through therefrigerant inlet connector 515, the refrigerant flows through the tubes505 between the header tanks 507 in a zigzag path, and finally is letout through the refrigerant outlet connector 517 of the header tank 507.During that time, the refrigerant flowing through the tubes 505exchanges heat with air passing outside the tubes 505.

Header Tank Configuration

The header tanks 507 will be mainly described with reference to FIGS. 31to 33.

Each header tank 507 includes a rectangular tube pipe 519, and lids 525closing opposite open ends 519 a, 519 a of the pipe 519. The pipe 519 isa combination of a first member 521 and a second member 523 dividedlongitudinally. The partition 527 for partitioning the interior spaceinto a plurality of chambers is disposed in the header tank 507.

Both of the first member 521 and the second member 523 are formed in a Cshape in cross section. Specifically, the first member 521 includes aflat base 529 orthogonal to the longitudinal direction of the tube 505,and a pair of straight portions 531 projected from opposite sides of thebase 529 in a generally orthogonal direction, forming a substantiallyC-shape cross section. The base 529 of the first member 521 has tubeinsertion slots 533 into which open ends of the tubes 505 are inserted.Like the first member 521, the second member 523 includes a flat base535 orthogonal to the longitudinal direction of the tube 505, and a pairof straight portions 537 projected from opposite sides of the base 535in a generally orthogonal direction, forming a substantially C-shapecross section. The base 535 of the second member 523 includes an opening(not shown) into which a tubular portion 541 of the refrigerant inletconnector 515 (or the refrigerant outlet connector 517) is inserted andfitted.

In this embodiment, the width dimension of the first member 521(distance between the pair of straight portions 531) is set larger thanthe width dimension of the second member 523 (distance between the pairof straight portions 537). The first and second members 521, 523 arebrazed to each other with outer peripheral surfaces of the straightportions 537 of the second member 523 fitted to inner peripheralsurfaces of the straight portions 531 of the first member 521.

The base 535 of the second member 523 is provided with support holes 543for supporting projections 526 a of the lids 525. Also, the straightportions 537 of the second member 523 are provided with support grooves545 for supporting wings 526 b, 526 b of the lids 525. The support holes543, 543 and the support grooves 545 in the second member 523 allow thelids 525 to be positioned in place. In this embodiment, the partition527 has the same shape as that of the lids 525. The partition 527 alsoincludes a projection 528 a and wings 528 b, and is positioned in placeby a support hole not shown and support grooves not shown formed in thesecond member 523.

The materials of the header tanks 507 will be mainly described.

The material of the first member 521 is a core material 521 a having abrazing material layer on either surface. The first member 521 formed ina predetermined shape (in a C shape) has a brazing material layer 521 con an outer peripheral surface of the core material 521 a, but has nobrazing material layer on an inner peripheral surface.

The material of the second member 523 is a core material 523 aintegrally formed with a brazing material layer 523 c on an entiresurface 523 c on either surface. The second member 523 formed in apredetermined shape (in a C shape) has the brazing material layer 523 con the outer peripheral surface of the core material 523 a.

The material of each lid 525 is a core material 525 a integrally formedwith brazing material layers 525 b, 525 c on both surfaces entirely(FIG. 33B).

The material of the partition 527 is a core material 527 a integrallyformed with brazing material layers 527 b, 527 c on both surfacesentirely (FIG. 33B).

When the members of the header tank 507 (the first member 521, thesecond member 523 and the rid 525) are assembled, a brazing materiallayer is located between joint surfaces of the members. Thus, brazing ofthe assembled members at a predetermined temperature causes the membersof the header tank 507 to be fixed in a unit.

Although the rids 525 and the partition 527 have no brazing materiallayers on their peripheries (surfaces to be brought into contact withinner peripheral surfaces of the first and second members 521, 523constituting a pipe), the brazing material layers 525 b, 525 c on bothsurfaces of the rids 525 and the brazing material layers 527 b, 527 c onboth surfaces of the partition 527 are melted to enter the peripheriesby capillarity during brazing. Consequently, the lids 525 and thepartition 527 are brazed to the first and second members 521, 523.

Tube Configuration

FIGS. 34 and 35A to 35C illustrate a tube 505. The tube 505 has atubular shape, and is brazed to the header tanks 507 with its oppositeends inserted into the tube insertion slots 533 in the header tanks 507.The tube 505 includes a corrugated inner fin 549.

With reference to FIGS. 35A to 35C, the manufacturing process of thetube 505 will be described. First, a metal plate M of a single elongatedplate with a core material 505 a integrally formed with a brazingmaterial layer 505 c on either surface is prepared as a material M ofthe tube 505.

Then, as shown in FIG. 35A, opposite side portions of the metal plate Mof an elongated plate material are rolled inward to form joint portions547.

Then, the material M is folded into two along the longitudinalcenterline so that the brazing material layer 505 c is located at theouter peripheral side of the tube 505. The joint portions 547 at theedges of the fold are joined together to form a tube. At that time, asshown in FIG. 34, the inner fin 549 is inserted in the tube 505. Thematerial of the inner fin 549 is a core material 549 a integrally formedwith brazing material layers 549 b, 549 c on both surfaces as shown inFIG. 34.

Finally, when the heat exchanger 1 is brazed as a whole, the jointportions 547 of the tube 505 are brazed to each other, and the innersurface of the tube 505 is brazed to the inner fin 549. As a result, thetube 505 is completed. At the same time, the outer surface of the tube505 is brazed to the outer fins 503, and outer surfaces at opposite endsof the tube 505 are brazed to the inner peripheries of the tubeinsertion slots 533 in the header tanks 507. Also, the members of theheader tank are brazed to each other.

In the eleventh embodiment, the inner fin 549 has the brazing materiallayers 549 b, 549 c on both surfaces of the core material 549 a, and isbrazed to the inner peripheral surface of the tube 505, avoiding contactwith the joint portions 547 of the tube 505.

Outer Fin

The material of the outer fin 503 is only a core material with nobrazing material.

Manufacturing Process of the Heat Exchanger

The process of manufacturing the heat exchanger 501 in this embodimentwill be briefly described.

First, the outer fins 503, the tubes 505, the inner fins 49, the membersof the header tanks 507 (the first and second members 521 and 523 andthe rids 525), the partitions 527, the connectors 515 and 517, and theside plates 511 and 511, which are made from predetermined materials,are prepared.

Then, these components are formed into their respective predeterminedshapes.

Then, all of the components are assembled and temporarily fixed by a jigor the like to be a temporary assembly.

Then, the temporary assembly is sintered in a furnace at a predeterminedtemperature to braze the components together. That is, brazing materiallayers of the components in the temporary assembly are melted at apredetermined temperature and then cooled, thereby to fix the componentsin a unit.

Functions

According to the eleventh embodiment, no brazing material layer isprovided to the inner surface of the tube 505, while the brazingmaterial layers 549 b, 594 c are provided to both surfaces of the innerfin 549 to join the tube 505 and the inner fin 549. The inner fin 549 isbrazed to the inner peripheral surface of the tube 505, avoiding contactwith the joint portions 547. Therefore, as shown in FIG. 34, a brazingmaterial flow cutoff portion S3 for separating brazing material insidethe tube 505 (the brazing material layers 549 b, 549 c on both surfacesof the inner fin 549) from brazing material outside the tube 505 (thebrazing material layer 505 c on the outer surface of the tube 5) isformed on the inner surface of the tube 505 near the joint portions 547.The brazing material flow cutoff portion S3 separates flow of thebrazing material inside the tube 505 from flow of the brazing materialoutside the tube 505 during brazing.

Effects

The effects of the eleventh embodiment will be summarized below.

First, according to the eleventh embodiment, as described above, sincethe brazing material flow cutoff portion S3 is provided for separatingthe brazing material inside the tube 505 (the brazing material layers549 b, 549 c on the two sides of the inner fin 549) from the brazingmaterial outside the tube 505 (the brazing material layer 505 c on theouter surface of the tube 505) so as to prevent flow of the brazingmaterial between the inside of the tube 505 and the outside of the tube505, the brazing material inside the tube 505 is prevented from flowingaway to the outside of the tube 505 through a joint surface between thejoint portions 547, and the brazing material outside the tube 505 isprevented from flowing away into the tube 505 through a joint surfacebetween the joint portions 547, during brazing.

Accordingly, no shortage of brazing material occurs inside the tube 505or outside the tube 505.

In the eleventh embodiment, the total joint area inside the tube 505(the total area of joint surfaces between the inner peripheral surfaceof the tube 505 and the inner fin 549) is larger than the total jointarea outside the tube 505 (the total area of joint surfaces between theouter peripheral surface of the tube 505 and the outer fins 503). Thus,the brazing material flow cutoff portion S3 prevents brazing materialoutside the tube 505 from flowing away into the tube 505 and causingshortage of brazing material outside the tube 505.

Second, according to the eleventh embodiment, the tubes 505 and theouter fins 503 are arranged alternately, and the header tanks 507 towhich the open ends of the tubes 505 are brazed and connected areprovided. Thus, the brazing material flow cutoff portions S3 act moreeffectively. Specifically, during brazing, brazing material of eachheader tank 507 (brazing material in the brazing material layer 521 c onthe outer surface of the first member 521 in this embodiment) can beprevented from being absorbed into the tubes 505 together with brazingmaterial in the brazing material layer 505 c on the outer surface of thetube 505, and running short. This is because, in the structure in whichthe tubes 505 are connected to the header tanks 507, during brazing,brazing material of the header tanks 507 can also flow into the tubes505 through joint surfaces between the joint portions 547 of the tubes505 together with brazing material in the brazing material layers 505 con the outer surfaces of the tubes 505.

Third, according to the eleventh embodiment, each outer fin 503 iscomprised of a core material having no brazing material layer on eitherside, so that no exchange of brazing material is made between the tubes505. Therefore, even a structure in which one of the tubes 505improperly has a larger joint area than the other tubes 505 can preventbrazing material from flowing in volume to and accumulating on thatparticular tube 505.

[Tube Modifications]

In the eleventh embodiment, tubes may be modified as described below aslong as each tube separates brazing material inside the tube (brazingmaterial layers on both surfaces of an inner fin) from brazing materialoutside the tube (a brazing material layer on the outer surface of thetube) so as to prevent flow of brazing material between the inside ofthe tube and the outside of the tube. In the description below,identical or like components are given like reference numerals, andthose components and their functions/effects will not be described.

[Tube Modification 1]

A tube 610 in a modification 1 shown in FIG. 37 is similar to the tube505 in the eleventh embodiment in FIG. 34 in that an elongatedplate-like material having a brazing material layer 610 c on an entiresurface to be the outer surface of a core material 610 a is foldedlongitudinally, and joint portions 611, 612 at opposite sides are brazedto each other, but is different from the tube 505 in the eleventhembodiment in the configurations of the joint portions 611, 612. Thetube 610 in the modification 1 also includes a brazing material flowcutoff portion S3 for preventing the flow of brazing material betweenthe inside of the tube 610 and the outside of the tube 610, and thusprovides the same effects as in the eleventh embodiment.

[Tube Modification 2]

A tube 620 in a modification 2 shown in FIG. 38 is also different fromthe tube 505 in the eleventh embodiment in FIG. 34 in the configurationof joint portions 621. The tube 620 in the modification 2 also includesa brazing material flow cutoff portion S3 for preventing the flow ofbrazing material between the inside of the tube 620 and the outside ofthe tube 620, and thus provides the same effects as in the eleventhembodiment.

[Tube Modification 3]

A tube 630 in a modification 3 shown in FIG. 39 is also different fromthe tube 505 in the eleventh embodiment in FIG. 34 in the configurationsof joint portions 631, 632. The tube 630 in the modification 3 alsoincludes a brazing material flow cutoff portion S3 for preventing theflow of brazing material between the inside of the tube 630 and theoutside of the tube 630, and thus provides the same effects as in theeleventh embodiment. The tube 630 in the modification 3 is differentfrom the tube 505 in the eleventh embodiment in that a surface of thejoint portion 632 having a brazing material layer 505 c is joined to asurface of the joint portion 631 having no brazing material layer.

[Tube Modification 4]

A tube 640 in a modification 4 shown in FIG. 40 is also different fromthe tube 505 in the eleventh embodiment in FIG. 34 in the configurationsof joint portions 641, 642. The tube 640 also includes a brazingmaterial flow cutoff portion S3 for preventing the flow of brazingmaterial between the inside of the tube 640 and the outside of the tube640, and thus provides the same effects as in the eleventh embodiment.The tube 640 in the modification 4 is different from the tube 505 in theeleventh embodiment and the tubes 610, 620, 630 in the modifications 1to 3 in that one of the joint portions 641, 642 at opposite sides of thematerial (the upper one 641 in this modification) is formed longer thanthe other joint portion (the lower one 642 in this modification), andthe joint portion 641 is bent in a substantially C shape to enclose thejoint portion 642. In brazing, the joint portions 641, 642 are brazed toeach other with an inner surface of the joint portion 641 in contactwith an outer surface of the joint portion 642 with a brazing materiallayer.

[Tube Modification 5]

A tube 650 in a modification 5 shown in FIG. 41 is also different fromthe tube 505 in the eleventh embodiment in FIG. 34 in the configurationof joint portions 651. The tube 650 in the modification 5 also includesa brazing material flow cutoff portion S3 for preventing the flow ofbrazing material between the inside of the tube 650 and the outside ofthe tube 650, and thus provides the same effects as in the eleventhembodiment.

The tube 650 in the modification 5 is different from the tube 505 in theeleventh embodiment and modifications 1 to 4 in that the joint portions651 are brazed at their inner surfaces having no brazing materiallayers. Generally, configuration with a brazing material layer providedto at least one joint portion like the tube 505 in FIG. 34 and the tubes610 to 640 in the modifications 1 to 4 will have better stability in ajoint. However, in the configuration of the tube 650 shown in themodification 5, brazing material layers 650 c on the outer surfaces ofthe joint portions 651 will come around into the inner surfaces of thejoint portions 651 through the edges, thereby ensuring the joint betweenthe joint portions 651.

Tubes 660 to 680 in modifications 6 to 8 to be described below aredifferent from the tubes 610 to 640 in the modifications 1 to 5 in thatthey are formed by combining a plurality of (two in those modifications)metal plates as materials.

[Tube Modification 6]

The tube 660 in the modification 6 shown in FIG. 42 is different fromthe tube 610 in the modification 1 in FIG. 37 in that two metal platesM1, M2 are used as materials, and joint portions 661, 662 at oppositesides of the metal plates M1, M2 are joined to one another, butotherwise is the same. Therefore, the same effects as those of the tube610 in the modification 1 in FIG. 37 can be provided.

[Tube Modification 7]

The tube 670 in the modification 7 shown in FIG. 43 is different fromthe tube 620 in the modification 2 in FIG. 38 in that two metal platesM1, M2 are used as materials, and joint portions 671 at opposite sidesof the metal plates M1, M2 are joined to one another, but otherwise isthe same. Therefore, the same effects as those of the tube 620 in themodification 2 in FIG. 38 can be provided.

[Tube Modification 8]

The tube 680 in the modification 8 shown in FIG. 44 is different fromthe tube 630 in the modification 3 in FIG. 39 in that two metal platesM1, M2 are used as materials, and joint portions 681, 682 at oppositesides of the metal plates M1, M2 are joined to one another, butotherwise is the same. Therefore, the same effects as those of the tube630 in the modification 3 in FIG. 39 can be provided.

In summary, according to the eleventh embodiment, no brazing materiallayer is provided to the inner surface of a tube and brazing materiallayers are provided to both surfaces of an inner fin to join the tubeand the inner fin. Since the inner fin is brazed to the inner peripheralsurface of the tube, avoiding contact with tube joint portions, brazingmaterial inside the tube (the brazing material layers on both sides ofthe inner fin) is separated from brazing material outside the tube (thebrazing material layer on the outer surface of the tube). Therefore,flow of molten brazing material during brazing is separated into flow ofbrazing material inside the tube and flow of brazing material outsidethe tube. As a result, during brazing, brazing material is preventedfrom flowing away from the inside of the tube to the outside of the tubeand causing a shortage of brazing material inside the tube, or brazingmaterial is prevented from flowing away from the outside of the tube tothe inside of the tube and causing a shortage of brazing materialoutside the tube.

The heat exchanger in the eleventh embodiment is a heat exchanger inwhich tubes and header tanks are brazed together with the tubes insertedinto tube insertion slots in the header tanks. Alternatively, it may bea heat exchanger in which tubular tank portions are formed atlongitudinal ends of tubes in such a manner as to project in a layeringdirection of the tubes, and the tank portions of the adjacent tubes inthe layering direction are brazed and connected to each other to formheader tanks. The eleventh embodiment may be a heat exchanger with noheader tanks like a serpentine-type one.

Although the invention has been described above by reference to certainembodiments of the invention, the invention is not limited to theembodiments described above. Modification and variation of theembodiments can be made without departing from scope of the appendedclaims. Therefore, the embodiments are only for illustrative purpose anddo not limit the invention.

1. A heat exchanger comprising: outer fins; a plurality of tubes havingopen ends and arranged alternately with the outer fins; and header tanksreceiving the open ends of the tubes for communication with the tubes,the header tanks each comprising a first member and a second memberwhich are combined to each other; wherein the first member includes tubeinsertion slots into which the open ends of the tubes are inserted, thesecond member lacking the tube insertion slots; the first member iseither a core material having no brazing material layers on outer andinner peripheral surfaces thereof, or a core material having a brazingmaterial layer on an outer peripheral surface thereof which does nothave brazing material layer on an inner peripheral surface thereof; andthe second member is brazed to the outer or inner peripheral surface ofthe first member which does not have brazing material layer thereon;wherein the first member does not have the brazing material layer on theinner peripheral surface thereof and has a brazing material layer on theouter peripheral surface thereof; and the second member is connected toan inner peripheral surface of the first member and brazed to the firstmember; wherein an edge of the first member is spaced from the outerperipheral surface of the second member.
 2. A heat exchanger as setforth in claim 1, wherein the first member and the second member of theheader tank each have a box-like shape with an opening formed in acombining direction to each other.
 3. A heat exchanger as set forth inclaim 2, wherein the second member has the brazing material layerthereon.
 4. A heat exchanger as set forth in claim 1, wherein: theheader tank includes a pipe comprising the first member and the secondmember, and lids for closing opposite open ends of the pipe; and thelids are connected in the pipe.
 5. A heat exchanger as set forth inclaim 4, wherein the second member includes the brazing material layerthereon.
 6. A heat exchanger as set forth in claim 4, wherein the lidseach have a plate-like shape, and have a brazing material layer on atleast one surface thereof.
 7. A heat exchanger as set forth in claim 1,further comprising a partition fitted in each header tank forpartitioning an interior space of the header tank into a plurality ofchambers, the partition being connected to the inner peripheral surfacesof the first and second members.
 8. A heat exchanger as set forth inclaim 7, wherein the partition has a plate-like shape, and the brazingmaterial layer on at least one surface thereof.